Electric meter.



W. M. STEMPEL.

ELECTRIC METER.

APPLICATION FILED FEB-27.1913.

Patented May 4, 1915,

2 SHEETS-SHEETI I I I WM Stamp QZ) W. M. STEMPEL.

ELECTRIC METER.

APPLICATION FILED FEB-27, 1913.

1,138,513. Patented May 4,1915.

2 SHEETS-SHEET 2.

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WALDEMAB M. STEMPEL, OF STATE COLLEGE, PENNSYLVANIA.

ELECTRIC METER.

Specification of Letters Patent.

' Patented M ya, rare.

Application filed February 27, 1913. Serial No. 751,076.

To all whom, it may concern Be it known that Ljlvnnonivmn M.

'STEMPEL, citizen of the United States, residing at State College,in-the county of Center and State of Pennsylvania, have invented certainnew and useful Improvements in Electric Meters; and I do declare thefollowing to be a full, clear, and-exact description of the invention,such as will enable others skilled in the art to which it apper- I tainsto make and use the same.

This invention relates to improvements in electric meters andparticularly to means for controlling the same from the power house.

One object of the invention is to provide a meter having a controllingmechanism whereby electric current may be served to customers at reducedrates during certain hours and at full rates at other hours.

Another object of the invention is to pr0- \ide means whereby thecontrolling mechanism of the meter is automatically regulated at thepower house. further object is to provide means for indicating to thecustomer exactly what rate he is paying at all times.

With these and other objects in View, the invention consists of certainnovel features of construction, combination and arrange ment of parts aswill be more fully described and claimed.

Figure l is a diagrammatic view of a direct current electric supplysystem and meter showing the application of my improved controllingmechanism. Fig.2 is a similar view of an alternating current supplysystem and meter showing the application of the invention thereto.

Refcrringmore particularly to Fig. 1 of the drawings wherein theinvention is shown applied to :1 Thompson watt-hour direct currentmeter, 1 denotes the motor, one end of the shaft of which is geared tothe usual or any approved mechanism for registering the energy consumed.The motor 1 comprises the armature 2 having the usual commutator 3,brushes 4., and field magnets 5. The brushes L and magnets 5 areconnected to the line wires 6 and 7 in the usual manner whereby thecurrent which passes through load. The pull on the armature will thus beequal to the product of the voltage on the line and the total currentused or simply the power dellvered. Fixed on the armature shaft 8 nearits lower end is an alununum disk 9 which rotates freely between thepoles of one or more suitably supported permanent magnets 10 which actas a drag on the disk 9. The magnets 10 are of such strength that thedrag applied thereby to the disk will be proportional to the speed ofrotation which produces the conditions desired in a watt-hour meter, andit follows that the total angular distance traveled by the armature willbe proportional to the total energy consumed. If the shaft of thearmature is properly connected up to a calibrated dial the total energyconsumed will bethereby added up and recorded.

The parts described in the foregoing are old and well known to theprofession and do not form a part of the present invention which ashereinbefore intimated, comprises means for automatically controllingthe speed of the. motor from the power house thereby causing the meterto register more slowly at certain times. 7 In carrying out my inventionI provide one or more electro-magnets 11 which are suitably supported inthe casing of the meter in such position that the disk 9. will revolvebetween the poles of the magnets as shown. The circuit or currentconducting wires 12 and 13, of the magnets 11, and which for convenienceI will designate as pilot wires run to the power house and are thereconnected-with an automatically operated controlling or'energizingmechanism which will now be described.

The energizing mechanism for the electromagnets 11, comprises amotor-generator set consisting of a motor 14 on the shaft of which isalso mounted the'armature 15 of a generator 16 which is driven by themotor in the usual manner. The generator 16 has a shunt coil 17 and aseries coil 18. The shunt coil is connected direct across the line,while the series coil is connected in series with the main bus-bars ofthe station so that the total current going out from the station goesthrough the series coil. The terminals of the'arniature of thisgenerator are connectcd to the pilot wires 12 and 13 which in turnconnect with the controlling ma nets 1]. in the customers meters ashereinbe ore described. The shunt coil 17 and the series coil 18 are soconnected that the current flows therethrough in opposite directions. Itwill thus be seen: that when the power station is delivering but littlepower, the series coil 18 is not effective. The generator 16 is thendelivering its maximum potential to the pilot wires thereby energizingthe electro-magnets 11 to their greatest ex tent which causes a heavydrag on the disk 9, causing the meter to record more slowly. By thisretardation the customer will obtain his energy or power at the minimumrates. As the load on the station increases the series coil 18 becomesmore and -more effective until, when the station is carrying'its fullload, the series coil 18 is designed to just neutralize the shunt coil17. When this occurs the generator will deliver no potential to themagnets 11 thereby permitting the, motor 1 to travel at normal speed atwhich time the power is supplied to customer at the maximum rates. Theintermediate loads at the station will have a graduated effect on themeter by energizing the magnets 11 to a greater or less extent. Assumingthat the customer is to pay a constant rate per kilo-watt-hour, thearrangement herein described has the effect of giving the customer moreenergy for the same amount of money or at a lower rate as will bereadily understood. The motor 14 is connected with the line wires 6 and7 in any suitable manner. In the present instance a shunt motor isshown, connected to the lines through a starting rheostat 19.

In the form of the invention hereinbefore described it has been assumedthat the coils regulating or controlling the magnets 11 of the variousmeters are connected in parallel to the wires feeding the same.

As stated in the beginning of this specification the arrangement ashereinbefore described is preferably used on direct current lines butthe same may be used on alternating current lines.

In Fig. 2 of the drawingsthe invention is shown applied to a differentform of meter, and as having a slightly different arrangement ofautomatic controlling mechanism at the power station. This latter formof the invention is designed to be used exclusively on alternatingcurrent lines. The type of the instrument shown in Fig. 2 is known tothe profession as an induction meter and is generally used inalternating current systems because of its simplicity of constructionand lack of a commutator, which, as is well known, necessarily retardsthe motion of the rotating part of the meter.

The motor shown in Fig. 2 comprises a revolubly mounted hgllow cylinder20 formed of aluminum. Suitably supported adJacent to the outer side ofthe cylinder portional to the voltage across the line. The

high inductance of this coil also makes the current therein lag behindthat in the coils 21 thus producing the effect of a rotating field whichcauses the cylinder 20 to revolve. The pull thus produced on thecylinder is, however, proportional to the product of the currentsflowing in the coils 21 and 21 and therefore to the power. As in thefirst form of motor, permanent magnets 25 are provided "in connectionwith the last described motor. The poles of these magnets 25 aredisposed on opposite sides of the cylinder 20 as shown. The magnets 25drag on the cylinder in direct proportion to the speed and since thepull of the coils 21 and 24'is proportional to the power, it followsthat the angular distance traveled by the aluminum cylinder will beproportional to the total energy consumed 'so that if the rotatingcylinder 20 is connected by means of suitable gearing to a properlycalibrated dial, this instrument can be made to sum up and record thetotal energy consumed in kilo-watt-ho'urs. The parts of this last formof meter which have just been described are well known and have beenherein particularly described simply to enable the invention whichis'applied thereto and hereinafter described, to be more readilyunderstood. The invention in this instance comprises a coil 26 arrangedon the core of the coil 24 and connected with pilot wires 27 runningback to the power house so that the current in the coil 26 will beexactly 180 degrees behind or ahead of that in the coil 21 as regardsphase. By this arrangement the coil 26 when energized, would counteractthe effect of the coil 24 and cause of the cylinder as will be readilyunderstood. While this last mentioned arrangement is not the mostdesirable there might be occasions when the same would be preferred.The. apparatus at the power station for automatically supplying theproper potential to the pilot wires 27 of the controlling coil 26comprises a transformer 28 having three coils 29, 30 and 31 on theprimary, and one coil 32 on the secondary.

essrs added to the transformer and the value of the' condenser is chosento make the coil 31 lead the coil 29 by the same amount as the coil 30lags behind 29. It might be here stated that either of the shunt coils30 or 31 may be dispensed with in some instances.

It has been found inpractice that some,

' power circuits will require one of these coils,

While other circuits will require the other or both of the coils asherein described. The secondary coil32 of the transformer is connectedto the pilot wires 27 leading to the controlling coil 26 in the meter.By this arrangement it will seem that when the power station is carryingno load the coil 29 is inactive and the coils 30 and 31 induce in thecoil 32 the maximum voltage. Coil 29 is so connected as to oppose thecoils 30 and 31 and as the load on the line increases the coil 29becomes more and more active, but being connected in opposition to thecoils 30 and 31 will reduce the voltage on the pilot wires thusgradually deenergizing or reducing the power of the controlling coil 26in the meter-until the full load is being delivered over the line andthrough the coil 29. The coil 29 will at this time exactly neutralizethe coils 30 and 31 thus rendering the coil 32 and the coil 26 in themeter inactive. The customers meters are thus made to change their speedfor a given power consumption, from a maximum to a minimum according toWhether the power station is carrying a full load or a light load.

It will be noted that if the load at the powerstation is increasedbeyond a full load. in the arrangement just described, the rate recordedby the meters, would begin to decrease again, owing to the overpoweringof the coil 29. This effect can be eliminated in two ways. One way is towind the coils so that the neutralization takes place at the allowableoverload insteadof at full load, or to add to the equipment anautomatically operated out out, hereinafter described, which breaks thecircuit of the controlling coils in the meters after a full load hasbeen reached. The first method would have the effect of furtherincreasing the rate "after reaching the full load, which might beobjectionable.

The circuit breaker or out out for the circuit of the controlling-code,hersinbefore referred to, comprises a switch arm 34 which is arranged inand positively connected at one end to one terminal of the wires and hasits other end normally held in engagement with the other terminal orcontact point 35- of the wires by a coiled spring 36. The spring .36 hasits opposite end connected with an adjusting screw 37 which is mountedin'a suitable support and has thereon an.

adjusting nut-38 whereby this tension of the spring 36 is regulated.Arranged in the mainline circuit wires is a solenoid 39 the core 40 ofwhich is connected with the switch arm'34 as shown. When thus arrangedthe entire current from the power plant goes through the coil of thesolenoid. The tension of the spring 36 is so adjusted that when thecurrent passing through the solenoid reaches its full load value thecore 40 of the solenoid will be retracted against the resistance of thespring 36 thus disengagin the switch arm 34 from the contact termina 35in the pilot wire circuit and breaking the latter. When the pilot wirecircuit is thus broken the controlling coils in the meters areimmediately deenergized which will per- .lnit the meters to record atfull rate until the load atthe power station is again reduced whereuponthe current in the solenoid is reduced to a sufiicient' extent to permitthe spring 36 to again'close the switch arm of the controlling coilcircuit thus again energizing the controlling coils in the meters to agreater or less extent in the manner described. In order to preventvibration of the switch arm and the consequent sparking at the contactpoint 35 when the switch arm is opened and closed, '1 preferably providethe pivoted end of the switch arm with a cam projection 34 with which isengaged a light curved spring 34 the pressureof which steadies theswitch arm and positively holds the samein an open or closed position.

- While the circuit breaker has been particularly described inconnection with the induction meter, it is obvious that this circuitbreaker may be employed with equal advantage with the Thompson type ofmeter and is here shown as being also arranged in the circuit of form ofthe invention.

It will be understood from the foregoing that during 0d peak periods,the meters do not measure or record actual kilo-watt hours, but instead,what might be called, equivalent kilo-watt hours, because the meters arerunning more slowly on off peak periods than at peak periods for thesame rate ofenergy consumption. In this case the equivalent kilo-watthours would mean such a number of actual kilo-watt hours which at themaximum rate would amount to the same money value as the actual kilowatthours charged at their various rates. Since ineither the Thompsontype ofmeter, or the induction type, herein demrihed, the

actual kilo-watt hours are not recorded during the off peak periods, thescale of measurement on the dial will necessarily have to be differentlymarked. Possibly equivalent kilo-watt hours might be used as previouslyexplained but it is much more preferable to calibrate the face of thedials in dollars and cents; In addition each meter may be provided witha rate indicator 41 having its scale calibrated so that it reads themaximum rate, (for instance 10 cents per kilo-watt hour) when there isno current flowing through the rate indicator, and the minimum rate (forinstance 2 cents per kilo-Watt hour) when the maximum current is passingthrough the pilot wire circuit and through the rate indicator.

It. will be plain from the foregoing that when the current in the pilotwire circuit is zero, the rate for power is at maximum and that when thecurrent in the pilot wire circuit is maximum the rate for power isminimum. It follows therefore, that if the rate indicator il be placedin the pilot wire circuit next to the meter, and so adjusted and thescale on the dial thereof so calibrated that it shows the maximum and"minimum rates as above described, the rate indicator becomes, in a way,a load factor meter, which will indicate to the customer what rate he ispaying at any moment, for the power he is using.

The rate indicator 41 may be of a very inexpensive type and if desired,can be made an integral part of the meter with which it is used. Thearrangement as herein shown and described enables the electrical companyto give all customers the benefit of a multiple rate without having todepend on the honesty of the customer who in case of reduced rates doesnot need to be asked to use power during certain hours of the day. Therate in dicator is desirable to the customer because it indicates tothem just what the company is doing. It will also be seen that theinvention as a whole makes it possible to treat all customers alike, toreduce the complications of the rate sheet, and to simplify the handlingof accounts.

I desire to here state that any or all of the devices used in the art tocorrect meters for changes of power factor, frequency, or

for any purpose are applicable to the meters herein. described and thatmy improvements as herein specified may be applied to any standardmeters without modifying the same except in minor mechanical details.

From the foregoing description taken in connection with the accompanyingdrawings, the'construction and operation of the invention will bereadily understood without requiring a more extended explanation.

Various changes in the form, proportion and the minor details ofconstruction may be resorted to without departing from the principle orsacrificing any of the advantages of the claimed invention. 1

Having thus described my invention, I claim:

1. In a system of distribution, the combination of a generator, a loadcircuit supplied thereby, a meter including a rotary element anauxiliary circuit, means included in sai load circuit and controllingsaid auxiliary circuit whereby the energization of the latter will beinversely proportional to the load on the former, and means in saidauxiliary circuit to influence the rotation of said rotary elementsubstantially as and for the purpose set forth.

2. In a system of distribution the combination of a generator, a loadcircuit supplied thereby, an electric meter including a ro tary element,means cooperating with the latter to retard the same, an auxiliarycircuit including said means, a source of supply forsaid auxiliarycircuit and means included in the load circuit for controlling saidsource of supply whereby the output of the latter will be inverselyproportional to that of the former. 1

3. In a system of electrical distribution, the combination with acurrent generator, and an electrical meter provided with a damping disk;of electric retarding. devices applied thereto, a supplemental generatorconnected with said retarding devices, and means included in thecircuitof said current generator for controlling the field of saidsupplemental generator, whereby when said current generator isdelivering full load said supplemental generator will be inactive andthe retarding devices in the meters thereby deenergized and whereby theload decreases said supplemental generator becomes more and more activethereby energizing said retarding devices and causing the meter torecord more slowly.

4. In a system of electrical distribution, the combination with acurrent generator, and an electrical meter provided with a damping disk;of a supplemental generator set of electro-magnets within whose fieldsthereby energizing said electro-magnets and causing the meter to recordmore slowly.

5. In a system of electrical distribution,

the combination with a current generator,

and an electrical meter provided with a damping disk; of a supplementalgenerator, retarding devicesapplied to said damping disk and includedwithin the circuit of said supplemental generator, means connected withsaid current generator for controlling cally operated when the latter isdelivering full load to operate said circuit breaker, thereby breakingthe circuit of said supplemental generator.

6. In an electric power distributing system, a meter having a motor, adisk fixed-on the shaft of said motor, electro-magnets arranged inposition to act as a drag' on said disk whereby the speed of the motoris controlled, an electric circuit connected with said magnets andextending to the power station of the system, a motor generator setarranged at the power station in the circuit of said electromagnets andconnected with the line wires of the system, a series coil arranged onsaid generator and connected in series with the line circuit, a shuntcoil arranged on said generator in opposition to said series coil andconnected across the line whereby when the load on the line is full saidseries coil will neutralize said shunt thereby rendering said generatorinactive and denergizing the electro-magnets in the meter and whereby asthe load on the-line decreases said series coil will become less activeand the shunt coil more active, thus energizin said electro-magnets to agreater or lesser egree.

In testimony whereof I have hereunto set my hand in presence oftwo'subscribing witnesses.

WALDEMAR M. STEMPEL. Witnesses O. E. Govmn, A. L. JOHNSTON.

